Improved intracellular probing techniques have been developed which permit reliable probing of all retinula cells and most lamina cells in Calliphora. These can also be marked by internal staining with procion yellow and permit ion injection studies of the cell ionic processes. The ion injection studies using wild and various mutants of Drosophila have provided a valid mathematical model of the roll of the calcium ions in the control of the membrane conductivity. Using white-noise stimulus theory, generalized models have been developed for the Diptera retinula cell generator properties. These contradict previous evidence on the process for ultraviolet light responses in retinula cells (1-6) of the Diptera and form a basis for determining the interactions between the photoreceptors and between the photoreceptors and certain higher level cells. Binocular pattern recognition by high level selective motion detection cells in the lobular-lobula plate of flies have been studied using spatio-temporal white-noise stimuli. These demonstrate distinct properties of depth of perception or object distance evaluation.